Archive for June, 2009

china daily questions official air quality statistics

Tuesday, June 30th, 2009

The story about the US Embassy’s BeijingAir air quality twitter feed (whose subscribers now top 2,200) was picked up by the China Daily today. Perhaps surprisingly, the China Daily article uses the embassy data to question whether the Beijing EPB’s official data present an accurate view of Beijing’s air quality:

China Daily calculated that only five days were above “moderate” level in May on BeijingAir, but the local environment bureau said on its website on May 31 that the capital’s air quality was the clearest during the same period since 2000, with 25 blue-sky days.

However, the article goes on to quote both an embassy official and a Chinese expert cautioning that the single station is not representative of Beijing’s overall air quality:

“This is a single site,” [US Embassy spokesperson Susan] Stevenson said. “It cannot be used to measure the air quality across the city. They can’t be compared.”

“The embassy is located in the central business district, which has heavy traffic, and its monitoring station cannot represent the overall picture,” Zhu Tong, an environment professor with Peking University, said yesterday.

Signficantly, the China Daily article does not question whether or not the embassy data is valid for that area, only whether the single data point can be extrapolated out to the rest of the city. To me, this is an important distinction, because collective agreement that the embassy data is valid should ultimately help pressure the Beijing EPB to set up their own real-time PM2.5 monitors across the city (which is the direction we should be driving in).

The article closes with this comment, noteworthy for its open questioning of air quality data. Such questioning is rare in the Chinese state-run media:

Some residents expressed doubts about the official air quality data.

Wang Haiyan, a 36-year-old Beijinger living in Chaoyang district, said that even under a different measuring system, there is still no reason to get such different air quality results.

Within Chinese-language media, Xinhua’s International Herald Leader (国际先驱导报) published a story two days ago (also printed with a different title in the Hong Kong-based Phoenix magazine (凤凰) here) on the US Embassy’s air quality reporting; the story included this photo that is apparently of the monitor:


As one would expect, the tone of the Xinhua piece is much more defensive of the official data and critical of the embassy. Unfortunately, I don’t have time now to write more on this; stay tuned tomorrow for some translation and commentary.

krugman’s indictment of climate change deniers

Monday, June 29th, 2009

ts-krugman-190Paul Krugman’s column today is highly recommended. It is a scathing indictment of climate change deniers in the US Congress:

But if you watched the debate on Friday, you didn’t see people who’ve thought hard about a crucial issue, and are trying to do the right thing. What you saw, instead, were people who show no sign of being interested in the truth. They don’t like the political and policy implications of climate change, so they’ve decided not to believe in it — and they’ll grab any argument, no matter how disreputable, that feeds their denial.

Because the overwhelming – and still increasing – scientific evidence demonstrates that climate change presents a “clear and present danger to our way of life, perhaps even to civilization itself,” he calls the denial of climate change “irresponsible and immoral.”

In an aside (and as an economist), he further bolsters his case with this zinger:

Given this contempt for hard science, I’m almost reluctant to mention the deniers’ dishonesty on matters economic. But in addition to rejecting climate science, the opponents of the climate bill made a point of misrepresenting the results of studies of the bill’s economic impact, which all suggest that the cost will be relatively low.

(Further info on the economic misrepresentation he mentions here and here.)

In the US-China climate debate, although there is still a lot to be settled, at the very least it seems that the top leadership of both nations agree on the core science of what is causing climate change and where we need to be – in terms of global emission reductions – by what date.

On this point, earlier this month, I was encouraged by what Todd Stern, the US’ top climate negotiator, had to say when speaking at the Center for American Progress:

Q: I wonder if you might comment, in talking to Chinese officials, do you feel you’re speaking on the basis of the same science?

MR. STERN: …I have not had a sense that [the Chinese] are in some completely different place with respect to what the underlying science is…in terms of the overall kind of dynamics – where we’re going, where need to go – I don’t think it’s a dramatically different assessment.

(Transcript here). Unfortunately, the same can’t be said for the US’ own legislature.

beijing epb responds to us embassy air quality twitter feed

Friday, June 26th, 2009

A friend tipped me to an article in today’s South China Morning Post (registration required) on the US Embassy’s Beijing air quality twitter feed.

Although the majority of the content of the SCMP piece echoes that published last week in other sources, there is one important bit of new information:

Du Shaozhong, deputy director of Beijing’s environment protection bureau, was unaware of the US embassy’s move, but said: “Any attempts to question our figures with a single monitoring station are not authoritative enough.”

This could get bad. Let’s see if it gets picked up by other media and begins to escalate.

FYI, the twitter feed has around 1600 followers now (up from 300 just a week ago).>

us embassy outed as source of beijingair twitter feed

Monday, June 22nd, 2009

On Friday of last week, Time’s Austin Ramzy outed the BeijingAir twitter feed as being set up and administered by the US Embassy:

The U.S. Embassy operates a single station in eastern Beijing that records levels of PM2.5, fine particles considered particularly dangerous to human health…

While the U.S. doesn’t actively promote the information, it has slowly been getting more attention from Beijing residents concerned about the city’s air quality. “The U.S. Embassy has an air quality monitor to measure PM 2.5 particulates on the Embassy compound as an indication of air quality,” says Susan Stevenson, a State Department spokesperson. “This monitor is a resource for the health of the Embassy community.” She cautions that citywide analyses cannot be done from a single machine, but because the embassy has the data available, it makes it available to others.

Before the story came out, there were around 300 followers of the feed; now there are more than 1,100 and rising fast.

Beijing experienced some bizarre and extremely rapid changes in air quality on Thursday and Friday of last week. On both days, BeijingAir reported maximum pollution levels (hazardous air, AQI = 500) for brief periods in the afternoon. However, hazardous air was never reported by either the Beijing EPB or MEP, presumably because the pollution spikes on both days were short-lived enough that the overall 24-hour averages evened out as just “light pollution.” (More discussion here and here.)

Here’s a graph showing BeijingAir and MEP-reported air quality over the period noon Tuesday to midnight Sunday last week. Because MEP has no system for real-time reporting, the extreme pollution spikes on the 18th and 19th were never truly reflected in MEP’s air quality data:

6 18 weekend beijingair with mep data

The events of last week highlight the need for real-time reporting of air quality in Beijing. I wonder if the growing popularity of the embassy’s twitter feed will ratchet up pressure on MEP / Beijing EPB to implement such a system here in Beijing.

Final note: the speed of the drop in pollution levels during the afternoon of 6/19 was stunning. With no technical background in air quality modeling or meteorology, I have no idea how this is even possible:

6 19 afternoon

more info on beijing’s 6/18 air quality

Friday, June 19th, 2009

Yesterday, beginning at around 10am, there was a sudden and dramatic spike of air pollution here in Beijing. I blogged about it here, and it was covered in the Guardian and Time’s blog, with surely more to come. The pollution spike lasted until close to midnight yesterday. I presume yesterday evening’s rain is what ended the event, although it should be noted that, as I write this, the pollution seems to be creeping up again.

Yesterday’s pollution spike may be seen very clearly in the BeijingAir tweeted hourly data over the past couple of days. Shown here are PM2.5 concentration and AQI:

6 18 beijingair data

Note the missing data points in the afternoon of 6/18 and the maxing out of AQI at 500 during the same period.

Despite yesterday afternoon’s stifling pollution, MEP’s officially reported Air Pollution Index (API) for 6/18 was just 104 – indicating “slightly polluted” air quality. The reason, as noted yesterday, is that MEP’s API does not report real-time air quality; it is an average air quality indicator covering noon to noon beginning from the previous day. Therefore, we wouldn’t expect the afternoon pollution spike of 6/18 to show up until the 6/19 reported data point.

However, the API for 6/19, which was released a few minutes ago, is just 159 (“lightly polluted”), which is significantly lower than I would have expected.

Edit: An API of 159 – corresponding to a PM10 concentration of 266 ug/m^3 – still represents awful air quality, despite my use of the word “just.” China’s daily/yearly goals for PM10 are 150/100 ug/m^3, while the WHO’s recommended targets are 50/20 ug/m^3.

The following graph shows MEP PM10 and API data, as well as BeijingAir PM2.5 and AQI data, for the last few days. Note that the absolute magnitudes of the BeijingAir and MEP data are not directly comparable due to slightly different measurements and scales. But the trending should be the same:

6 18 beijingair with mep data

Although the MEP data increases beginning noon on 6/18, as one would expect, the increase just doesn’t seem commensurate with the seemingly atrocious pollution yesterday afternoon and evening.

What’s going on here? Well, there are a few options, but I’m not sure which one is correct:

First – it’s theoretically possible that, because MEP averages over 24 hours over a number of different monitoring stations, the overnight reduction combined with lower pollution outside the city center brought the overall average down. Here is the daily individual monitor data from the Beijing EPB:

beijing epb

There are certainly some high readings, e.g. Dongsi, but there are also some that report only half as bad (Pinggu, Miyun).

Second – it is possible that the BeijingAir monitor is either not calibrated correctly or suffered some unusual activity (e.g. a car idling for an extended period outside the monitor). This seems unlikely.

Third – I’m not sure if this is correct or not, but it may be possible that the pollution event was largely PM2.5 – particles of diameter smaller than 2.5 microns – that do not register in the EPB’s monitoring stations designed to measure PM10. Can anyone comment on this?

Fourth – I don’t think I need to write this option explicitly.

More info as I learn it.

air in beijing hazardous

Thursday, June 18th, 2009

BeijingAir is currently reporting hazardous air quality in Beijing (there was an error in the most recent hour, but you can see the PM2.5 concentration slowly creeping up over the course of the morning and early afternoon):

beijingairtwitter 6 18

Note, though, that with the AQI maxed out at 500, the air quality is theoretically worse than “hazardous,” whatever that might be.

On the other hand, MEP is reporting an API today of 104, “slightly polluted.”

A few people have asked me about this blatant discrepancy, so here’s a brief comment:

It’s important to remember that MEP’s reported API for 6/18/09 is actually an average API for the period noon to noon 6/17 to 6/18. Given that this current pollution spike seems to have rolled in over the course of the late morning and early afternoon, it is reasonable that the impact has not yet registered in the MEP reported data. From the perspective of MEP’s official reporting, we will have to wait until around 2pm tomorrow to see the results of this episode.

Of course, this discrepancy highlights the necessity of working towards a system of real-time air quality reporting (like the AIRNow program in the US) in Chinese cities. (More on this in another post.)

Final note: during my time in Beijing (3.5 years), I’ve only experienced a handful of days in which MEP reported a 500 API. The most recent ones were 12/28/2007 and 12/12/2006, plus a few during the sandstorm season of the spring of 2006. I am curious to know if tomorrow will yield another.

symmetric characters

Wednesday, June 17th, 2009

This is an off-topic post continuing in an occasional series on Chinese character esoterica.

As an engineer, I am a bit obsessed with the structures and patterns of individual Chinese characters.

Recently (don’t ask how), I stumbled upon the character , and it got me thinking about symmetry within characters. Specifically, how many characters out there are symmetric across both the x and y-axes? Here are the ones I could think of:


I’m sure there’s more out there; anyone think of any?

Lastly, this exercise reminds me of a Chinese character riddle a colleague once shared with me: starting from 日, by adding one stroke, you can make 9 different characters. Can you think of them all?

how clean were april and may?

Monday, June 8th, 2009

This past spring, the months of April and May in Beijing were reported as the cleanest April / May in a decade. (Sources for April: China Daily and Beijing EPB, see also my previous post; sources for May: Xinhua and Beijing EPB.)

Independent of the quantitative results, these reports seem to confirm what a lot of people have been mentioning to me, that this past spring has seemed surprisingly clean.

Let’s evaluate the truth in all of this. The following graph shows average API*, average PM10 concentration, and number of Blue Sky Days for the period April-May from 2005 through 2009:

april may

From these numbers, the results are pretty clear: the period April-May 2009 in Beijing was indeed significantly better in terms of air quality than the same period in any of the previous four years. (I could have looked farther back, but I decided only to look at five years total for this analysis.)

Here are some comparisons of 2009 vs 2005-2008 averages:

april may 2

I think it’s probably fair to say that the air quality this April and May was 30-40% better than the average air quality during the same period over the previous four years.

As usual, we should celebrate the progress while being mindful of the significant improvements still required. My calculated average PM10 concentration for this period, 117 ug/m^3, is still well above China’s annual target (100 ug/m^3) and well well above the WHO’s ideal target for developed nations (20 ug/m^3). It is also well above my estimate for the average PM10 concentration during last year’s two-month Olympic period (79 ug/m^3).

Summary of Beijing’s 2009 first quarter air quality
Summary of Beijing’s 2008 air quality
Update on fall air quality in Beijing

*I don’t really like averaging API, because it can lead to some misleading results (further discussion in this post), but despite that I still think it has value as an indicator here.

frozen in time – beijingair twitter feed shows exact hour twitter was blocked in china

Friday, June 5th, 2009

beijingairtwitterThe BeiingAir automatic Twitter feed is stuck at 6/2, 4:00pm, just before Twitter was blocked in China.

I’m working on some analysis for another post related to the BeijingAir Twitter feed, which automatically tweets hourly PM2.5 concentrations at a single station in Beijing.

In looking at the data just now, though, I realized that it hasn’t updated since June 2nd at 4:00pm, shortly before Twitter was harmonized in China.

It may be just a robotic scientific instrument (a Met One Bam 1020), but don’t you think it still had its feelings hurt? Let’s all hope for a prompt release of Twitter so Bam can get back to doing what it does best.

Update 6/8/09: Twitter is back, and so is the feed:

beijingairtwitter 2
Looks like Twitter was officially blocked for 5 days, 22 hours…

excellent summaries of status of us-china climate change negotiations

Friday, June 5th, 2009

Last week, describing US-China negotiations related to climate change, Rep. Edward Markey quipped, “This is going to be on one of the most complex diplomatic negotiations in the history of the world.”

The netisphere is grateful this week to the incredible series of posts from both Charlie McElwee of China Environmental Law and Julian Wong of the Green Leap Forward /Center for American Progress on this topic.

First up, Charlie’s series on both China and the US’ positions six months out from Copenhagen, including tremendous summaries of the diplomatic challenges as well as in-fighting going on within each country:

6/1: Copenhagen Countdown China’s Climate Change Position
6/2: Copenhagen Countdown US’ Climate Change Pposition
6/3: Copenhagen Countdown T-6 Months Wrap Up
6/4: No Climate Deal Without China

(Also recommended is his three-part series from February: US China Climate Change Engagement Part 1, Part 2, and Part 3.)

Charlie’s posts are so good, that having read them just before watching Todd Stern’s talk Wednesday at CAP, I was left with the distinct feeling that I wish Mr. McElwee were the US’ top climate negotiator instead of Mr. Stern…

Next, Julian’s great work for CAP on exactly what China has been up to on the climate front:

6/3: Climate Progress in China: A Primer on Recent Developments
6/4: China Begins Its Transition to a Clean Energy Economy

Like Charlie’s posts, these are comprehensive summaries that – along with the myriad links contained within them – are recommended reading both for people just getting up to speed on these issues and those buried deep in them.

Lastly, I haven’t posted too much on the US-China climate change negotiations largely because I think others out there (like Charlie and Julian) are already doing a terrific job. However, I did want to show one figure that I think is at the core of why this is such a diplomatic challenge. I like to call this this figure if you only look at one graph this year related to US-China climate negotiations, make it this one:

us china emissions

Source: the Asia Society’s Roadmap for US-China Cooperation on Energy and Climate Change

This is an excellent figure, because it encompasses in parallel perhaps the three most important numbers (both absolute and relative) that matter for each country going into the US-China climate dialogue. It is critical that all three of these graphs be acknowledged simultaneously, because the selective ignoring of any one can drastically change one’s perspective on who bears responsibility for acting and on what scale.